Re: JIT compiling with LLVM v9.1

On 29 January 2018 at 22:53, Andres Freund <andres(at)anarazel(dot)de> wrote:

> Hi,
>
> On 2018-01-23 23:20:38 -0800, Andres Freund wrote:
> > == Code ==
> >
> > As the patchset is large (500kb) and I'm still quickly evolving it, I do
> > not yet want to attach it. The git tree is at
> > https://git.postgresql.org/git/users/andresfreund/postgres.git
> > in the jit branch
> > https://git.postgresql.org/gitweb/?p=users/andresfreund/
> postgres.git;a=shortlog;h=refs/heads/jit
>
> I've just pushed an updated and rebased version of the tree:
> - Split the large "jit infrastructure" commits into a number of smaller
> commits
> - Split the C++ file
> - Dropped some of the performance stuff done to heaptuple.c - that was
> mostly to make performance comparisons a bit more interesting, but
> doesn't seem important enough to deal with.
> - Added a commit renaming datetime.h symbols so they don't conflict with
> LLVM variables anymore, removing ugly #undef PM/#define PM dance
> around includes. Will post separately.
> - Reduced the number of pointer constants in the generated LLVM IR, by
> doing more getelementptr accesses (stem from before the time types
> were automatically synced)
> - Increased number of comments a bit
>
> There's a jit-before-rebase-2018-01-29 tag, for the state of the tree
> before the rebase.

If you submit the C++ support separately I'd like to sign up as reviewer
and get that in. It's non-intrusive and just makes our existing c++
compilation support actually work properly. Your patch is a more complete
version of the C++ support I hacked up during linux.conf.au - I should've
thought to look in your tree.

The only part I had to add that I don't see in yours is a workaround for
mismatched throw() annotations on our redefinition of inet_net_ntop :

src/include/port.h:

@@ -421,7 +425,7 @@ extern int pg_codepage_to_encoding(UINT cp);

/* port/inet_net_ntop.c */
extern char *inet_net_ntop(int af, const void *src, int bits,
- char *dst, size_t size);
+ char *dst, size_t size) __THROW;

src/include/c.h:

@@ -1131,6 +1131,16 @@ extern int fdatasync(int fildes);
#define NON_EXEC_STATIC static
#endif

+/*
+ * glibc uses __THROW when compiling with the c++ compiler, but port.h
reclares
+ * inet_net_ntop. If we don't annotate it the same way as the prototype in
+ * <inet/arpa.h> we'll upset g++, so we must use __THROW from
<sys/cdefs.h>. If
+ * we're not on glibc, we need to define it away.
+ */
+#ifndef __GNU_LIBRARY__
+#define __THROW
+#endif
+
/* /port compatibility functions */
#include "port.h"

This might be better solved by renaming it to pg_inet_net_ntop so we don't
conflict with a standard name.

--
Craig Ringer http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Training & Services